U.S. patent number 7,279,641 [Application Number 11/550,637] was granted by the patent office on 2007-10-09 for wiring board and wiring apparatus.
This patent grant is currently assigned to Canon Kabushiki Kaisha. Invention is credited to Noriyuki Shikina.
United States Patent |
7,279,641 |
Shikina |
October 9, 2007 |
Wiring board and wiring apparatus
Abstract
A wiring board includes conductive wirings, terminals and
interconnecting lines connecting between them. First terminals
establish a one-to-one correspondence with the interconnecting
lines. The interconnecting lines terminate at the first terminals
except at least one of the interconnecting lines. The
interconnecting line which does not terminate at the first
terminals terminates at the second terminal. The first terminal at
which the interconnecting lines do not terminate is connected to
the third terminal. The first terminals are connected to outputs of
a driver IC mounted on a tape carrier package. The second and third
terminal are connected to a switch via a through lead line of tape
carrier package. When the second and third terminals are
short-circuited by the switch, all the outputs of the driver IC is
connected to the conductive wiring of the wiring board. When the
second terminal is connected to the detection circuit by the
switch, a signal on the wiring board is detected to determine a
position of a pen.
Inventors: |
Shikina; Noriyuki (Yokohama,
JP) |
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
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Family
ID: |
38093616 |
Appl.
No.: |
11/550,637 |
Filed: |
October 18, 2006 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20070117415 A1 |
May 24, 2007 |
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Foreign Application Priority Data
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Oct 21, 2005 [JP] |
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2005-307888 |
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Current U.S.
Class: |
174/254; 349/150;
361/777; 439/49 |
Current CPC
Class: |
G02F
1/13338 (20130101); G02F 1/13452 (20130101); G06F
3/0412 (20130101); G06F 3/046 (20130101); H05K
1/147 (20130101); H05K 1/117 (20130101); H05K
3/361 (20130101); H05K 2201/09781 (20130101) |
Current International
Class: |
H05K
1/02 (20060101) |
Field of
Search: |
;439/65,49,55 ;361/777
;349/150-151 ;174/254 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2-60186 |
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Feb 1990 |
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JP |
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9-319520 |
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Dec 1997 |
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JP |
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10-49301 |
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Feb 1998 |
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JP |
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Primary Examiner: Zarroli; Michael C.
Attorney, Agent or Firm: Morgan & Finnegan LLP
Claims
What is claimed is:
1. A wiring board, comprising: a plurality of conductors disposed
on a substrate; a plurality of interconnecting lines extended from
said plurality of conductors to a peripheral portion of the
substrate; a plurality of first terminals provided at the
peripheral portion of the substrate, wherein the number of the
first terminals is the same as that of the interconnecting lines;
and a second terminal and a third terminal adjoining the first
terminals, wherein the interconnecting lines are disposed so that
they establish one-to-one correspondence with the first terminals
and terminate at associated first terminals except at least one of
the interconnecting lines, and wherein said at least one of the
interconnecting lines which does not terminate at the first
terminals is connected to the second terminal, and the first
terminal at which said at least one of the interconnecting lines
does not terminate is connected to the third terminal.
2. A wiring apparatus, comprising: a wiring board according to
claim 1; a first circuit apparatus, attached to the wiring board,
including a drive circuit for generating and outputting a voltage
or current to be supplied to the conductors; first lead lines for
connecting the first terminal to an output of the drive circuit,
and a pair of lead lines for leading the second terminal and the
third terminal to a second circuit apparatus, respectively; a
detection circuit, disposed outside the wiring board, for detecting
a voltage or current generated in a conductor; and the second
circuit apparatus, attached to the first circuit apparatus,
including a detection circuit for detecting a voltage or current
generated in the conductors and a switch connected to the pair of
lead lines of the first circuit apparatus for switching between an
operation for short-circuiting the pair of lead lines and an
operation for connecting one of the pair of the lead lines which is
connected to the second terminal to an input of the detection
circuit.
3. A wiring apparatus according to claim 2, wherein the drive
circuit is an integrated circuit chip and the first circuit
apparatus is a tape carrier package mounting the integrated circuit
chip.
4. A wiring apparatus according to claim 3, wherein the switch of
the second circuit apparatus is connected to the tape carrier
package on a side opposite to the wiring board.
5. A wiring apparatus according to claim 2, wherein the second
terminal of the wiring board and the switch of the second circuit
apparatus are provided in a plurality of second terminals and a
plurality of switches, the plurality of switches being successively
switched so as to connect an associated second terminal to an input
of the detection circuit.
6. A wiring apparatus according to claim 2, wherein the detection
circuit has two inputs and detects a voltage between the two inputs
or a current passing between the two inputs when connected, and
wherein said display apparatus further comprises a circuit for
short-circuiting two conductors connected to associated second
terminals when the second terminals are provided in at least two
second terminals and are connected to the two inputs.
7. A wiring apparatus according to claim 2, wherein the plurality
of conductors are divided into a plurality of groups of
conductors.
8. A wiring apparatus according to claim 7, wherein the detection
circuit is a common detection circuit to the plurality of groups of
conductors.
9. A wiring board according to claim 1, wherein the wiring board is
a display panel and the plurality of conductors comprise scanning
lines and signal lines.
Description
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a wiring board including a
substrate provided with a wiring pattern and a wiring apparatus
including the wiring board and a circuit. More specifically, the
present invention relates to a display panel provided with wiring
for display and a display apparatus in which a circuit for sending
a signal to the wiring is attached to the display panel.
A display apparatus having a position indication function for
effecting input operation by touching a button on a display screen
with a hand-held pen or a finger has been put into practical use as
game machines, personal computers, automated teller machines,
ticket-vending machines, etc. In most of these apparatuses, an
input function is provided by superposing a transparent touch
sensor on a display panel. In such apparatuses, however, a sensed
position of an object on the display panel often deviates from its
true position because the display panel and the sensor panel are
stacked with a distance. They are not suitable for fine indication
of position or handwritten character input.
The display panel is provided with wiring for sending signals in a
vertical direction and a horizontal direction, so that it is
possible to effect input free from positional deviation if the
wiring can be used for detecting a position.
Japanese Laid-Open Patent Application (JP-A) Hei 9-319520 discloses
a method of detecting a current passing through wiring. More
specifically, a matrix display substrate on which a photoelectric
conversion element is disposed is irradiated with light from an
input pen to change an electric resistance at a light irradiation
portion and a scanning voltage is successively applied to either
one of electrodes disposed in X and Y directions to detect a
current passing through the other electrode, thus detecting a
light-irradiated position.
In JP-A Hei 10-49301, a loop circuit is formed using a pair of
scanning lines or signal lines of a matrix display. An
electromagnetic signal induced by an input pen is detected through
a detecting circuit, which is prepared in the driving IC chip.
Scanning lines or signal lines are short-circuited at the opposite
end to the detecting circuit by a switch. By changing the pair of
the lines forming the loop sequentially, position of the loop
circuit is scanned the screen. The position pointed by the pen is
determined from the maximum output loop in the scanning lines and
signal lines.
In the above-described methods, the scanning lines or the signal
lines are used for both of display and detection, so that these
wirings are connected to a drive circuit during a display operation
and connected to a detection circuit during a detection operation.
In JP-A Hei 10-49301, the drive and detection circuits are in the
driver IC and connected to a panel through a terminal. A switch is
formed therein so that the switch can switch between connection of
the terminal with the drive circuit and connection of the terminal
with the detection circuit.
In most of the display apparatuses a drive signal is supplied from
the outside of the display panel. In an active matrix display
apparatus, a scanning signal to be applied to scanning lines is
supplied from horizontal sides of a panel and a video data signal
to be applied to source lines is supplied from vertical sides of
the panel. For this purpose, a tape carrier package (TCP) mounting
a driver IC (integrated circuit) is frequently employed.
This TCP mounting method is a typical drive circuit mounting method
for display apparatus. TCP is a film as a base material at a center
of which a driver IC chip is mounted. Lead lines are patterned on
the film base material through photolithography. They are extended
from terminals connected with the integrated circuits, which are
called inner leads, to connection terminals at a periphery of the
film base material, which are called outer leads. Some of the outer
leads are connected to the display panel and the other outer leads
are connected to a printed wiring board.
When a pen input function, wherein scanning/signal lines are used
as an antenna for position detection, is added to a display panel
using driver ICs of the TCP mounting method, there arises the
following problem.
In order to switch between drive and detection, it is required that
the driver ICs are provided with a position detection function as
proposed in prior arts or a signal is detected from terminals other
than the connection terminals of TCP.
However, the driver ICs having the position detection function are
currently expensive. When such a driver/detection IC is newly
prepared, integration density is lowered and the number of driver
ICs necessary to a display panel is increased from one to two or
more. Thus, the preparation of a new IC having the position
detection function requires excessive cost.
Further, even when the scanning/signal lines for position detection
are provided with terminals, other than those of TCP, to which a
detection circuit is connected, it is necessary to disconnect the
scanning/signal lines from the driver ICs on the TCP during
detection. For this purpose, it is possible to consider that a
switch train for connecting/disconnecting the driver ICs to/from
the display panel is created in the display panel through TFTs and
the scanning/signal lines are led to a side where the TCP is not
connected and are connected with a detection circuit. However, the
connection of the TCP undesirably requires a large space at a
peripheral portion, i.e., a frame of the display panel.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a
display-integrated position detection apparatus without adding any
new function to the driver IC nor changing wiring pattern of the
TCP. The present invention provides a display-integrated position
detection apparatus which requires little modification of the
peripheral members of the display panel.
According to an aspect of the present invention, there is provided
a wiring board, comprising:
a plurality of conductors disposed on a substrate;
a plurality of interconnecting lines extended from said plurality
of conductors to a peripheral portion of the substrate;
a plurality of first terminals provided at the peripheral portion
of the substrate, wherein the number of the first terminals is the
same as that of the interconnecting lines; and
a second terminal and a third terminal adjoining the first
terminals,
wherein the interconnecting lines are disposed so that they
establish one-to-one correspondence with the first terminals and
terminate at associated first terminals except at least one of the
interconnecting lines, and
wherein said at least one of the interconnecting lines which does
not terminate at the first terminals is connected to the second
terminal, and the first terminal at which said at least one of the
interconnecting lines does not terminate is connected to the third
terminal.
According to another aspect of the present invention, there is
provided a display apparatus, comprising:
the wiring board described above;
a first circuit apparatus, attached to the wiring board,
including
a drive circuit for generating and outputting a voltage or current
to be supplied to the conductors;
first lead lines for connecting the first terminal to an output of
the drive circuit, and a pair of lead lines for leading the second
terminal and the third terminal to a second circuit apparatus,
respectively;
a detection circuit, disposed outside the wiring board, for
detecting a voltage or current generated in a conductor; and
the second circuit apparatus, attached to the first circuit
apparatus, including a detection circuit for detecting a voltage or
current generated in the conductors and a switch connected to the
pair of lead lines of the first circuit apparatus for switching
between an operation for short-circuiting the pair of lead lines
and an operation for connecting one of the pair of the lead lines
which is connected to the second terminal to an input of the
detection circuit.
These and other objects, features and advantages of the present
invention will become more apparent upon a consideration of the
following description of the preferred embodiments of the present
invention taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a matrix of display apparatus of
First Embodiment.
FIG. 2 is a schematic view showing a pixel electrode and a pixel
circuit.
FIG. 3 is a schematic view showing wiring at a peripheral portion
of terminals in First Embodiment.
FIG. 4 is a wiring diagram of TCP on which a driver IC is
mounted.
FIG. 5 is a circuit diagram of a driver board in First
Embodiment.
FIG. 6 is a schematic view of a matrix display apparatus of Second
Embodiment.
FIG. 7 is a schematic view showing wiring at a periphery of
switching substrate side terminals in Second Embodiment.
FIG. 8 is a circuit diagram of a switching substrate in Second
Embodiment.
FIG. 9 is a schematic view showing wiring at a periphery of
short-circuit substrate side terminals in Second Embodiment.
FIG. 10 is a circuit diagram of a short-circuit substrate in Second
Embodiment.
FIGS. 11(a) to 11(c) are schematic views for illustrating a
coordinate detection operation in Second Embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the present invention, such a board that a wiring pattern is
formed, on a substrate, with an electroconductive member is
referred to as a "wiring board". When the wiring board has a
function of display or position detection, it is called a display
panel or a position detection panel.
The wiring board is connected to an external circuit, from which an
input signal is sent to the wiring on the board. As a result, a
display device and another active element disposed on the board are
driven. Alternatively, a signal generated on the wiring board is
sent to the external circuit through the wiring. As a result, a
signal generation position or signal intensity is detected.
In the present invention, an apparatus including such a wiring
board and the external circuit attached thereto and exhibiting the
display function or the position detection function when it is
driven is referred to as a "wiring apparatus". The wiring apparatus
having the display function is referred to as a "display
apparatus", and the wiring apparatus having the position detection
function is referred to as a "position detection apparatus".
Further, the wiring apparatus having both the display function and
the position detection function is also sometimes referred to as
the display apparatus.
Hereinbelow, embodiments of the present invention will be
described. Herein, the present invention does not depend on the
type of a display apparatus but is applicable to a liquid crystal
display apparatus, an electrophoretic display apparatus, and other
many display apparatuses. Further, the present invention is also
applicable to any panel in which an electrode has both of a
function of applying a voltage or a current and a function of
detecting the voltage or the current.
Further, the display apparatus of the present invention may be of
an active matrix type or a simple matrix type or may include a
display panel in which an electrode having any shape is disposed.
The display apparatus may also be such a display apparatus or input
apparatus that XY coordinates are identified by applying a voltage
to an X-direction electrode so as to detect a voltage or a current
in Y-direction or applying a voltage to a Y-direction electrode so
as to detect a voltage or a current in X-direction.
1. First Embodiment
FIG. 1 is a constitutional view of a matrix display apparatus.
On a display panel 10, scanning signal lines (scanning lines) 14
disposed in parallel with each other on a substrate and signal
lines 14' disposed in parallel with each other on the substrate and
perpendicular to the scanning signal lines 14 are formed in a
manner of crossing with an overpass or underpass. At each of
intersections of the scanning lines 14 and the signal lines 14', a
pixel 11 of a display device is disposed.
An enlarged view of the pixel 11 is shown in FIG. 2. In the pixel
11, a pixel electrode 12 and a thin film transistor (TFT) 13 are
formed. A gate electrode of the TFT 13 is connected to the scanning
line 14 and a source electrode of the TFT 13 is connected to the
signal line 14'. Further, at a drain electrode, an auxiliary
capacity 15 for holding a writing signal received at timing of a
scanning signal is formed. The display panel 10 shown in FIG. 1 is
an active matrix display panel.
On the left side of the display panel 10, a TCP 60 on which a
driver IC for driving the scanning lines 14 is mounted is attached.
In FIG. 7, the scanning lines 14 are connected to the TCP 60 so
that they are divided into three groups. However, the number of the
groups may appropriately be determined depending on the number of
the scanning lines and the number of output of the driver IC. The
TCP is connected to a driver board 20 on an opposite side to the
display panel 10. The driver board 20 is formed of a resin
substrate on which interconnecting lines are printed. Through the
driver board 20, power and an input signal are transmitted to the
driver IC on the TCP.
On the signal line side, similarly, driver ICs are attached through
six TCPs 60' which are connected to a driver board 20'.
Hereinbelow, description is made on the assumption that the display
panel is the active matrix display panel and the scanning lines
(gate lines) and the signal lines (source lines) are disposed
perpendicular to each other.
In the present invention, the scanning lines and the signal lines
are equal in structure to each other, i.e., have the same wiring
structure and the same connection structure. For this reason,
members on the signal line side correspond to those on the scanning
line side are distinguished by simply adding an apostrophe(') to
associated reference numerals for the members on the scanning line
side. In the following description, the members on the scanning
line side are described as an example. However, the description
also holds true for the members on the signal line side.
FIG. 3 is an enlarged view of an end portion of the display panel
10.
On the display panel 10, the scanning lines 14 extend in an
X-direction and are connected with lead-out interconnecting lines
200 at their ends. These lead-out interconnecting lines 200
connected with the scanning line 14 terminate at a plurality of
connection terminals 16 disposed at a peripheral portion of the
display panel 10. In the present invention, a part of the
connection terminals 16 has a particular constitution which will be
described later more specifically.
FIG. 4 is a schematic wiring diagram of the TCP 60 connected to the
display panel 10.
At a central portion of the TCP 60, a driver IC 61 is mounted.
Output terminal inner leads of the driver IC 61 and panel-side
outer leads are connected by interconnecting lines 62. Further,
input terminals of the driver IC 61 are connected with outer leads
on the printed wiring board 20 side by interconnecting lines
63.
Most of TCPs are provided with dummy outer leads 66x and 68x
outside the outer leads 66 and 68, respectively. The panel-side
dummy outer leads 66x and connected with the display panel to
reinforce the connection of the display panel with the TCP. They
are also used for supplying voltages to interconnecting lines,
other than the scanning/signal lines provided on the display panel,
such as connecting signal lines for connecting the scanning lines
and the signal lines and connecting signal lines for connecting
adjacent TCPs.
Thus, the dummy outer leads are also used for supplying the voltage
or current to the display panel, so that they are disposed both on
the display panel side as those 66x and on the printed wiring board
side as those 68x on the printed circuit board side as those 68x.
The dummy outer leads 66x and 68x are connected by through
interconnecting lines 64 not via the driver IC.
The display panel of the present invention is based on the
precondition that it is connected with the TCP including the dummy
outer leads 66x and 68x and the through interconnecting lines 64.
Most of commercially available TCPs have such a structure, so that
they can be connected with the display panel of the present
invention.
FIG. 5 is a schematic view showing terminals and circuits of the
printed wiring board 20.
To the printed wiring board 20, the input-side outer leads 68 of
the TCP 60 are connected. The printed wiring board 20 is provided
with a plurality of terminals 28 for supplying power and input
signal to the driver IC 61 and a plurality of toners 27 to which
the dummy outer leads 68x are connected. The terminals 27 of the
printed wiring board used in combination with the display panel of
the present invention are connected to the switch circuits 21, 22,
. . . on the substrate with two terminals as one pair. Each of the
switch circuits 21, 22, . . . effects switching such that one
terminal A of the two terminals (as one pair) is short-circuited
with the other terminal B or connected with an external terminal C.
Timing of switching is controlled by a control circuit 510.
Hereinbelow, an embodiment of the present invention will be
described with reference to FIGS. 3-5.
The display panel 10 is provided with the connection terminals 16
for receiving the driving signal at the peripheral portion thereof.
The connection terminals 16 are required that they are disposed in
the same number and pitch as the panel-side outer leads 66 of the
TCP 60 shown in FIG. 4.
The connection terminals 16 are provided in the same number as the
scanning lines 14 of one group and in the same number as the
lead-out interconnecting lines 200.
The arrangement of the output terminals 66 of the driver IC 61
correspond to that of the scanning lines 14 on the display panel,
so that the connection terminals 16 are required that they not only
have the same number as the scanning lines 14 (the number is taken
as N) pertaining to one group on the display panel but also are
arranged in one-to-one correspondence manner in the order of the
scanning lines 14 of the display panel. More specifically, the
lead-out interconnecting lines 200 are extended to a position of
the connection terminals 16 while keeping the arrangement order of
the scanning lines 14 without intersection with each other on the
way to the scanning lines 14.
In FIG. 3, the scanning lines 14-1 to 14-N (N: the number
pertaining to one group to be connected with one TCP) correspond to
the connection terminals 16-1 to 16-N, respectively.
The display panel 10 of the present invention is provided with
eight other connection terminals 16a to 16g (generally even in
number) outside the connection terminals 16 to which the outputs of
the driver IC of the TCP 60 are connected (hereinafter, the
connection terminals 16 are referred to as "first connection
terminals"). These connection terminals 16a to 16g other than the
first connection terminals are also connected to the outer leads of
the TCP, so that they are arranged at the same pitch as the first
connection terminals.
The interconnecting lines 200 connected to the scanning lines 14
terminate at the first connection terminals except a part thereof.
In FIG. 3, all the lead-out interconnecting lines other than four
interconnecting lines including two interconnecting lines for the
scanning lines 14-1 and 14-2 at one outer end portion and two
interconnecting lines for the scanning lines 14-(N-1) and 14-N at
the other outer end portion terminate at corresponding first
connection terminals 16-3 to 16-(N-2), respectively.
The four lead-out interconnecting lines extended from the scanning
lines 14-1, 14-2, 14-(N-1), and 14-N do not terminate at the first
connection terminals. Instead, they are connected to four
connection terminals 16-a, 16-b, 16-c, and 16-d, respectively, of
the connection terminals provided outside the first connection
terminals (hereinafter, these four connection terminals are
referred to as "second connection terminals").
Further, of the first connection terminals, first connection
terminals 16-1, 16-2, 16-(N-1) and 16-N at which the lead-out
interconnecting lines 200 do not terminate are connected to
remaining four connection terminals 16e, 16f, 16g and 16h,
respectively, provided outside the first connection terminals
(hereinafter, the remaining four connection terminals are referred
to as "third connection terminals"). This connection is effected
via interconnecting lines 210 provided at a further outside panel
peripheral portion of the connection terminals 16.
By the above described wiring, the second connection terminals are
connected to the scanning lines (or the lead-out interconnecting
lines) which do not terminate at the first connection terminals and
the third connection terminals are connected to the first
connection terminals at which the scanning lines (or the lead-out
interconnecting lines) do not terminate. As described above, the
scanning lines and the first connection terminals establish
one-to-one correspondence including the arrangement order, so that
the second connection terminals and the third connection terminals
also establish one-to-one correspondence based on that between the
scanning lines and the first connection terminals. In FIG. 3, the
one-to-one correspondence is established between 16a and 16f, 16b
and 16f, 16c and 16g, and 16d and 16h, respectively.
The second connection terminals and the third connection terminals
are led out, as they are, to the terminals 27 of the printed wiring
board 20 via the through interconnecting lines 64 when the TCP is
mounted.
In correspondence with the second connection terminals and the
third connection terminals which are provided on the display panel
10 as eight connection terminals in total (generally even in
number), four switches 21-24 are provided on the printed circuit
board 20. The respective switches effect switching such that the
terminal A is short-circuited with the terminal B or connected with
the terminal C. For each switch, the terminal A is connected to the
line extended from the second connection terminal and the terminal
B is connected to the third terminal correspond to the second
connection terminal of the terminal A.
Based on these connections, the switches 21-24 select whether the
second connection terminal is directly connected to the third
terminal or connected to an external circuit. Further, as the
external circuit, a detection circuit 50 for detecting a signal on
the display panel is prepared.
As a result, it is possible to effect switching between two modes
including a display operation for connecting the scanning lines of
the display panel to the driver ICs by switching the switches 21-24
on the printed wiring board 20 and a position detection operation
using the scanning lines on the display panel as a detection
antenna.
In FIG. 3, the four scanning lines of all the scanning lines are
selected to be lead out to the outside but the number of such
selected scanning lines is not limited to four. For example, it is
also possible to use five or more scanning lines in the detection
operation. In the case of a position detection device such that
inputs is effected by touching a screen with a finger, high
accuracy is not required. For this reason, the number of the
scanning lines may be decreased to approximately 1/100 of the
entire scanning line number. When the number of scanning lines
selected for detection is n, the second connection terminal and the
third connection terminal are required to be n+n, i.e., 2n in total
number. This is the reason why the connection terminals other than
the first connection terminals are provided in even number.
2. Second Embodiment
In this embodiment, the present invention is applied to a display
panel in which a drive circuit is connected at both sides of
scanning lines. In order to prevent signal delay, application of
the same voltage signal from both sides of one signal line or one
scanning line is frequently effected in a large-screen panel.
FIG. 6 is a schematic view showing a constitution of the display
panel of this embodiment.
A display apparatus 100 includes a display panel 10 having a large
number of pixels 12 disposed horizontally and vertically in a
lattice-like shape. Around the display panel 10, a printed wiring
board 20 on a scanning line drive circuit side, a printed wiring
board (short-circuit board) 30 on an opposite scanning line drive
circuit side, a printed wiring board 40 on a signal line drive
circuit side, and a printed wiring board (short-circuit board) 50
on an opposite signal line drive circuit side are disposed.
Further, to the printed wiring boards 20 and 40 on the respective
drive circuit sides, a scanning line coordinate detection circuit
80 and a signal line coordinate detection circuit 90 are connected,
respectively. The display apparatus may further include a control
circuit 85 for controlling a display image on the display panel
10.
Between the display panel 10 and the printed wiring board 20 and
between the display panel 10 and the printed wiring board 40, three
TCPs 60 are connected. Similarly, three TCPs 70 are connected
between the display panel 10 and the short-circuit board 30 and
between the display panel 10 and the short-circuit board 50.
The TCPs 60 and 70 relaying the connections between the display
panel 10 and each of the printed wiring boards 20, 30, 40 and 50 is
formed by mounting a driver IC 61 on a flexible film member
provided with a lead-line pattern and are connected to the display
panel 10 by tape automated bonding (TAB) method.
2-1. Operation on Switching Board Side
First, an operation on the printed wiring board 20 as a switching
board will be described.
FIG. 7 is a schematic view showing wiring at a portion where the
driver TCP 60 for the scanning lines and the switching board 20 are
connected.
With respect to scanning lines 14a, 14b, 14c and 14d selected for
effecting position detection, there are no corresponding first
connection terminals and no outer leads on the TCP 60 side.
The first connection terminals are disposed with a spacing through
which the scanning line 14a, 14b, 14c and 14d pass and are
connected to second connection terminals 16a, 16b, 16c and 16d,
respectively. The second connection terminals 16a, 16b, 16c and 16d
are relayed to outer leads 66 of the TCP 60 and are further
connected with through interconnecting lines 69, opposite-side
outer lead 67, and terminals 27a, 27b, 27c and 27d of the switching
printed wiring board 20 to be connected to associated A terminals
(each being a common terminal for two terminals of 27a to 27d) of
switches 21, 22, 23 and 24.
On the other hand, respective terminals of the driver IC 61 for
supplying a scanning signal to scanning lines 14aa, 14bb, 14cc and
14dd adjacent to the scanning lines 14a, 14b, 14c and 14d,
respectively, are connected to third connection terminals 16e, 16f,
16g and 16h. The third connection terminals 16e, 16f, 16g and 16h
are relayed to the through interconnecting lines 69, the
opposite-side outer leads 67, and terminals 27a, 27f, 27g and 27h
of the switching printed wiring board 20. As a result, the
respective terminals of the driver IC 61 for supplying a scanning
signal to the scanning lines 14a, 14b, 14c and 14d are connected to
B terminals 21b, 22b, 23b and 24b of the switches 21, 22, 23 and
24.
Accordingly, when the A terminal and the B terminal are connected
by the switch 21, an output of the driver IC 61 is connected with
the first connection terminal of the display panel 10 to drive a
corresponding scanning line 14aa and enters a dummy outer lead of
the TCP 60 via the third connection terminal 16e, enters the
printed wiring board 20 via the through interconnecting lines 69,
returned again to the dummy outer lead of the TCP 60 and the
through interconnecting lines 69 via the switch 21, and supply a
signal to the scanning line 14a via the second connection terminal
16a of the display panel 10. The scanning lines 14a and 14aa are
driven by the same signal.
Operations of other switches 22-24 are the same as the switch
21.
The input terminals, grounding terminals, and power supply
terminals of the driver IC 61 are relayed to the switching printed
wiring board 20 via the input-side outer leads 68 and the printed
wiring board 28 and are connected to the control board 85 via the
switching printed wiring board 20. A display control circuit of the
control board 20 develops image data to be displayed on the display
panel 10 to form a scanning line image and generates s writing
signal and a scanning signal.
FIG. 8 is a circuit diagram of the switches 21, 22, . . . on the
switching printed wiring board 20 shown in FIG. 6.
In FIG. 8, the A and B terminals of the switch 21 are omitted. The
switch 21a between the B terminal and the C terminal is connected
with one terminal of the switch 21c of a switch array 25 disposed
on the same printed wiring board 20. The other terminal of the
switch 21c is connect together with other terminals to a coordinate
detection circuit 81 of the coordinate detection portion 80.
On the switching printed wiring board 20, switches 151, 152, . . .
to be connected to the scanning lines are disposed with a certain
spacing from the switches 21, 22, . . . A switch 151a between B and
C terminals of the switch 151 is relayed to one terminal of a
switch 151c and the other terminal of the switch 151c is connected
together with other terminals to a common terminal which is
connected to a grounding electrode-side terminal of the coordinate
detection portion 80.
Two switches, carrying to scanning lines disposed with a certain
spacing, e.g., the switches 22c and 152c are closed and other
switches are opened, whereby a voltage between the corresponding
two scanning lines is detected by the coordinate detection circuit
81.
The switches 21, 22, . . . of the switching printed wiring board 20
causes a short-circuit between the A and B terminals during image
writing periods and a short-circuit between the A and C terminals
during position detection periods each set between adjacent image
writing periods, thus being connected to the switch array 25,
During the coordinate detection, the scanning line subjected to the
coordinate detection is disconnected from the output terminal of
the driver IC.
The switch array 25 connects a pair of scanning lines 14 located on
the display panel 10 with a predetermined spacing to the coordinate
detection circuit 81. The pair of scanning lines 14 are
successively switched to move the pair of scanning lines 14
subjected to the coordinate detection on the display panel 10.
2-2. Operation of Short-Circuit Board 30
ON an opposite side to the side where the switching printed wiring
board 20 is disposed on the display panel 10, the TCP 70 mounting
thereon the driver IC and the short-circuit printed wiring board 30
are attached.
Wiring of the TCP 70 has a mirror-image relationship with the TCP
60.
FIG. 9 is a schematic view showing the wiring of the short-circuit
printed wiring board 30.
scanning lines 14a, 14b, 14c and 14d selected for effecting signal
detection have no corresponding first connection terminals on the
short-circuit printed wiring board 30 and no outer leads of the TCP
70 similarly as in the case of the switching printed wiring board
20. The first connection terminals are located with a spacing
through with the scanning lines 14a, 14b, 14c and 14d passes and
are connected to second connection terminals 17a, 17b, 17c and 17d,
respectively. Subsequent connections and operations are identical
to those in the case of the switching printed wiring board 20.
FIG. 10 is a schematic view showing only switches on the
short-circuit printed wiring board 30.
As shown in FIG. 10, switches 31a, 32a, . . . between the B and C
terminals of the switches 31, 32, . . . are connected to terminals
of switches 31c, 32c, . . . of the switch array 25. All other
terminals of the switches 31c, 32c, . . . are short-circuited.
When the switch 32c of the switch array 25 and a switch 252c
corresponding to a pair of scanning lines disposed on the display
panel with a certain spacing from the switch 32c are closed and
other switches are opened, the pair of scanning lines disposed with
the certain spacing creates a loop circuit as shown in FIG. 10.
As a result, two inputs of the switching-side coordinate detection
circuit 80 creates a loop circuit through the scanning lines, so
that electromagnetic wave generated from an input pen on the
display panel is detected as induced current.
The switch arrays 20 and 25 from a loop circuit by short-circuiting
plural pairs of scanning signal lines 14 on the display panel 10
pair by pair. Further, by successively switching the pair of
scanning lines 14 to be short-circuited, the loop circuit subjected
to the position detection is moved on the display panel 10. As a
result, the loop position on the display panel is scanned. A
position at which a maximum induced current is generated during the
scanning is detected as a position of the input pen.
As shown in FIG. 6, with respect to the signal lines 15 for
supplying a writing voltage signal corresponding to image
information, the switching printed wiring board 40, the
short-circuit printed wiring board 50, and the coordinate detection
portion 90 are disposed.
Operations similar to those in the case of the scanning line side
are effected with respect to a plurality of selected wiring signal
lines 15, whereby the position of the input pen is determined.
<Coordinate Detection Circuit>
Principle of coordinate position detection by pen inputting in the
present invention will be described.
FIG. 11(a) is a schematic view showing arrangement of a pen 110 on
the display panel 10 (hereinafter referred to as a "position
indicator") and loop circuits L1, L2 and L3. FIG. 11(b) is a graph
showing electromotive force detection values of the loop circuits
L1, L2 and L3 varying depending on X-coordinate positions of the
position indicator 110. FIG. 11(c) is a graph for illustrating
position detection processing on the basis of the electromotive
force detection values of the loop circuits L1, L2 and L3.
As shown in FIG. 6, the display apparatus 100 includes the position
indicator 110 on the image display screen. The position indicator
110 contains an AC power source therein and an output coil at a tip
portion thereof. From the tip portion, electromagnetic wave is
emitted to generate induced current in the loop circuit for
Y-coordinate detection and the loop circuit for X-coordinate
detection.
As shown in FIG. 11(a), on the display panel 10, the first loop
circuit L1, the second loop circuit L2, and the third loop circuit
L3 which have the same size are formed. The position indicator 110
is moved in the X-direction.
In this case, as the position indicator 110 is closer to a center
of the loop circuit, an amount of magnetic flux penetrating the
loop circuit is larger. As a result, as shown in FIG. 11(b), the
first loop circuit L1, the second loop circuit L2, and the third
loop circuit L3 provides peaks, of electromotive force (voltage or
current), different in X-position of the position indicator by
induction of the electromagnetic wave from the position indicator
110.
When the position indicator 110 indicates a coordinate position Xp,
the coordinate detection portion 90 detects electromotive force
values of the first loop circuit L1, the second loop circuit L2,
and the third loop circuit L3 as intersections of the coordinate
position Xp with a broken line.
The detection values of electromotive force the first to third loop
circuits L1 to L3 are subjected to interpolation approximation with
quadric curves as those at center positions of the first to third
loop circuits L1 to L3. The X-coordinate positions of peaks of the
quadric curves are subjected to arithmetical operation to determine
X-coordinate positions of the position indicator.
As described above, the electromotive force value of the loop
circuit on the display panel 10 using the writing signal lines 15
selected with the predetermined spacing is detected by the
coordinate detection portion 90 and subjected to interpolation
calculation to determine the X-coordinate value of the position
indicator.
Similarly, an electromotive force value of a loop circuit on the
display panel 10 using scanning signal lines 14 selected with a
predetermined spacing is detected by the coordinate detection
portion 80 and subjected to interpolation calculation by the
control board 85 to determine a Y-coordinate value of the position
indicator 110.
While the invention has been described with reference to the
structures disclosed herein, it is not confined to the details set
forth and this application is intended to cover such modifications
or changes as may come within the purpose of the improvements or
the scope of the following claims.
This application claims priority from Japanese is Patent
Application No. 307888/2005 filed Oct. 21, 2005, which is hereby
incorporated by reference.
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